The present invention relates to the field of filling and/or emptying of gas cylinders. The invention provides a novel apparatus and method of filling such cylinders, wherein the time required for filling is substantially reduced. The invention also reduces or eliminates the dangers associated with insufficient tightening or overtightening of cylinder connectors.
It is common practice to use pressurized cylinders to store and distribute various industrial gases, such as oxygen, nitrogen, argon, etc. Such cylinders contain relatively small quantities of gas, to accommodate the varying needs of customers. A substantial component of the cost of distribution of the gases is the labor required to fill each cylinder.
Because the gases mentioned above are held at high pressure, they can be dangerous if not handled properly. For this reason, the Compressed Gas Association (CGA) publishes standards for the valves used on gas cylinders, and for their associated connectors. For example, differently shaped connectors are used for different gases, to prevent the accidental connection of one type of gas to a cylinder intended for another type of gas. Also, the standards require the use of right-handed threads for connectors used for non-flammable gases, while left-handed threads are used for flammable gases.
Adherence to the above standards helps to insure that the connection of the gas source to the gas cylinder will be secure. But no safety standard can serve its purpose if the connection is not properly made. Thus, if the connector is not tightened sufficiently, there is a likelihood of gas leakage. And if the connector is overtightened, the threads on the connector can be damaged.
In general, the cylinder valves used in the prior art include a threaded connector, either male or female, which is adapted to receive the threaded end of a flexible but airtight hose. The threaded connector includes a central spud which defines a channel for gas flow, and a threaded collar, disposed around the spud, for providing the threaded engagement with the cylinder valve. The threaded collar must be tightened securely onto the cylinder connector. In the prior art, it has been necessary to tighten the collar manually, either by turning a handwheel attached to the threaded connector, or by the use of a wrench adapted to turn a hex nut.
The safety precautions necessary in handling compressed gases increase the time required to fill gas cylinders, especially when a large number of cylinders are to be filled. Each threaded connector must first be tightly engaged with the cylinder valve connector before filling can begin. After the filling is completed, the connector must be unscrewed, requiring almost the same amount of time and effort.
The prior art contains many examples of methods and apparatus for filling gas cylinders. However, the prior art known to applicant deals only with the filling operation, but not the process of connecting a filling hose to the cylinder. For example, U.S. Pat. No. 4,153,083 discloses a regulated system for filling a plurality of gas cylinders. U.S. Pat. No. 4,446,895 shows an apparatus for filling a gas cylinder, the apparatus including a piston means disposed within the cylinder for controlling the introduction of gas into the cylinder. U.S Pat. No. 3,799,218 shows apparatus for dispensing compressed gas at predetermined pressure and volume. U.S. Pat. No. 2,411,235 discloses apparatus for filling gas cylinders, the apparatus being partly automated, and being capable of portable use. U.S. Pat. No. 2,645,907 shows apparatus for filling a plurality of gas cylinders with measured quantities of gas. U.S. Pat. No. 2,530,523 shows apparatus for filling of gas cylinders, the apparatus providing improved control in the "topping off" portion of the cylinder filling cycle. All of the disclosures of the above-cited patents are incorporated herein by reference.
The present invention discloses an apparatus which greatly facilitates the connection of a gas line to a cylinder valve. Use of the present invention can reduce the time required for connection of the line to the cylinder by up to 80%. The invention is designed to operate with virtually all standard gas cylinder connectors. Thus, the invention can be used in conjunction with most, if not all, of the devices described in the patents cited above. The invention also includes a method of automatic gas cylinder connection.